Pv Training Manual

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Training Manual

Photovoltaic System

Green Empowerment Palang Thai

In coordination with

Karen Health and Welfare Department

Taipei Overseas Peace Service, Thailand

Zoa Refugee Care


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Table of Contents

1.0 Introduction ---------------------------------------------------------------------------------4

1.1 Summary of Components-----------------------------------------------------------------5

2.0 How a Solar Panel Works----------------------------------------------------------------6

3.0 Basic Power Terms-------------------------------------------------------------------------7

3.1 The Difference Between DC and AC-----------------------------------------------------7

3.2 Power That a Solar Panel Produces-----------------------------------------------------8

3.3 Watts VS Watt-Hours------------------------------------------------------------------------9

4.0 The Sun as a Resource-------------------------------------------------------------------10

4.1 Perfect Sun Hours---------------------------------------------------------------------------10

4.2 Orientation-------------------------------------------------------------------------------------13

5.0 How Solar Panels Function------------------------------------------------------------14

5.1 IV Curves--------------------------------------------------------------------------------------15

5.2 Changes in IV Curves----------------------------------------------------------------------16

6.0 The Charge Controller-------------------------------------------------------------------17

7.0 Wiring-------------------------------------------------------------------------------------------18

7.1 Terminations-----------------------------------------------------------------------------------18

7.2 Wire Sizing-------------------------------------------------------------------------------------18

8.0 Batteries---------------------------------------------------------------------------------------21

8.1 Types of Batteries----------------------------------------------------------------------------22

8.2 Depth of Discharge--------------------------------------------------------------------------23

8.3 State of Charge ------------------------------------------------------------------------------23

8.4 Battery Safety---------------------------------------------------------------------------------24

9.0 Inverters---------------------------------------------------------------------------------------25

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10.0 Designing a PV System------------------------------------------------------------------26

10.1 Calculating Total Daily Consumption in Watt-hours---------------------------------27

10.2 Efciency of PV System--------------------------------------------------------------------28

10.3 Sizing the Panel------------------------------------------------------------------------------3110.4 Sizing the Battery----------------------------------------------------------------------------33

11.0 System Installation-------------------------------------------------------------------------35

11.1 Parallel and Series---------------------------------------------------------------------------35

11.2 Installation of the Solar Panel-------------------------------------------------------------37

11.3 Controller Installation------------------------------------------------------------------------40

11.4 Installation of the Battery-------------------------------------------------------------------41

11.5 Wiring Installation----------------------------------------------------------------------------41

11.6 Light Switch Installation--------------------------------------------------------------------42

11.7 Load Connections---------------------------------------------------------------------------42

12.0 Load Management-------------------------------------------------------------------------43

13.0 Trouble Shooting---------------------------------------------------------------------------46

13.1 Wire Connections----------------------------------------------------------------------------47

13.2 Battery------------------------------------------------------------------------------------------47

13.3 Solar Panel------------------------------------------------------------------------------------48

13.4 Check Load Terminals----------------------------------------------------------------------48

14.0 About Us--------------------------------------------------------------------------------------49

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1.0 Introduction

This book is designed to be used as a manual for the training of how to design, install and maintain photovol-

taic (solar panel) systems. It is not made to stand alone as a book that a person reads on their own. Rather, this

book is more of a workbook that can be used to help in the training of those who will be installing and using

the system. Furthermore, the goal of this manual is not to go in depth into all of the intricacies of photovoltaic

systems, but rather provide the student with the practical information so that he or she will nish the training

with knowledge on how to troubleshoot and maintain their PV system. Finally, we hope that this workbook will

be a useful resource in the future when the trainees are called upon to maintain, troubleshoot, design or install a

system.

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1.1 Summary of Components

A. Solar Panel - Converts sunlight to electricity.

B. Batteries - Store electricity.

C. Charge Controller - Manages the ow of electricity between the solar panel battery and load.

D. Inverter - Converts DC power from the solar panel and battery to AC power. Inverters are notalways used. When they are used they can be combined with the same piece of equipment at

the charge controller

E. Load - Application for electricity, e.g. lights, LED light, computer, radio.

F. Wires - Connect the other various components together.

(A)

(B)

(C)

(C) (D)

(E)

(F)

(A)

(B)

(F)

(E)

(E)

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2.0 How a Solar Panel Works

The solar panel only creates electricity when there is sun. The below picture depicts that when it is sunny the

solar panel captures the energy from the sun and converts it into electricity and turns on the light. When there is

no sun, the panel does not make electricity and there is no light.

This is the most simplistic type of solar panel system. In Fig. 3, the light will only work when there is enough

sun for the solar panel to produce electricity.

A loadis a piece of electri-

cal equipment that consumes

energy. For example, when

a light bulb is on it is a load

because it is consuming en-

ergy through electric wire

it is connected to.

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3.1 The difference between DC and AC

There are two types of electricity: direct current electricity (DC) and alternating current electricity (AC). Alter-

nating current is the type of current most commonly used in households that are connected to the grid to power

loads such as, radios, TVs, refrigerators, and lighting.

Direct current is used mostly in houses that are not connected to the grid, and are running off of batteries.

A solar panel produces DC electricity, and a battery stores DC electricity. Fig. 4a shows a diagram of direct cur-rent, where the current does not change. Alternating current electricity turns on and off 60 times a second.

Current is the ow of the

electricity through a wire.

Figure 4. AC VS. DC Electricity.

(a) Direct Current (b) Alternating Current (WWF - Energy & Galapagos)

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A wattis the amount of power that asolar panel can produce or that a lightbulb consumes.

3.3 Watts vs. Watt-Hours

A watt-houris the amount of energythat a solar panel can produce or alight bulb can consume in a certainnumber of hours.

Watt Hours = Watt X # of Hours

Power= Watts Energy= Watt-Hours

For example, a 13 watt light bulb requires power of 13 watts to light up.

If a 13 watt light bulb is lit for 3 hours, it consumes energy of 13 watts X 3 hours or 39 watt-hours:

13 Watts X 3 Hours = 39 Watt-Hours

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4.0 The Sun as a Resource

In order to design a photovoltaic system, we need to understand how much sun the area in which we are install-

ing the PV system will receive. For most regions of the world, the daily average of sun received is known. The

average amount of sun received is given in the units of PSH or Perfect Sun Hours.

A Perfect Sun Hour (PSH) represents a one hour period of a perfectly sunny day with no clouds. Therefore if a

region has a PSH of 4 it means that on average, the region will receive 4 hours of perfect sun per day. A PSH is

equivalent to having 1000 W/m2(watts per meter squared) of sun for one continuous hour.

PSH is found by adding up all the amount of sun received for every hour of the day and then dividing the total

by 1000 W/m2. Below in Fig. 5, the curve shows the amount of sun received per hour over the day and the box

shows the total number of perfect sun hours in the day. Table 1, on the following page, shows one example of

calculating PSH.

4.1 Perfect Sun Hours (PSH)

Figure 5. Diagram of Peak Sun Hours (PSH).

(www.homepower.com)

Understanding how the Earth receives light from the sun is extremely important in designing a photovoltaic

system. This section explains some of the basics of how the sun works and how we measure the strength of the

sun at different locations.

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Peak Sun Hours

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Hour Watts / m2 Watt Hours / m2

5AM - 6AM 0 0

6AM - 7AM 25 257AM - 8AM 25 25

8AM- 9AM 50 50

9AM - 10AM 300 300

10AM - 11AM 1000 1000

11AM - 12 PM 1200 1200

12PM - 1PM 1000 1000

1PM - 2PM 300 300

2PM - 3PM 50 50

4PM - 5PM 25 25

5PM - 6PM 25 25

6PM - 7PM 0 0

TOTAL Watt-hrs / m2 / Day 4000

Every hour of the day the sun will produce a different amount of power (watts) per meter squared. To nd out

how many perfect hours of sun are present in a day, the amount of watt hours / m2 is added up and then divided

by 1000 W / m2.

Watt hours / m2 / day = Hours of Perfect Sun per Day 1000 Watts / m2

Unfortunately, every day does give the same amount of sun. Therefore before we can know the PSH for a

certain area, we need to do the above calculation for every single day of the year and calculate the average. For

example, in the Amazon region of Ecuador the PSH is 3. Some days there have a PSH of 5 and other days havea PSH of 1, but on average the PSH is 3. Conveniently, we do not need to do the above calculations because

scientists have been collecting this information for many years and have created maps like the map on the fol-

lowing page in Fig. 6. Although world maps of PSH are generated for a given season and are too broad to use

for actual design, they provide a good illustration of what the PSH values are around the world.

4000 Watt hours / m2 / day = 4 PSH 1000 Watts / m2

Table 1

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Fig

ure6.WorldMapofPSH.

ThisisamapoftheworldshowingthePSH

foreverypartoftheworld

(http://w

ww.sunwize.com/info_

center/insolmap.h

tm)

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4.2 Orientation

Once we know the solar resource it is very important to mount the panel correctly so that we capture as much

sun as possible. Solar panels produce the most electricity when they are perpendicular to the sun. Since the sun

moves all day, it is not practical to keep moving the panel all day to keep it perpendicular to the sun.

In general, the best average position for mounting the panel is tilted towards the equator at an angle approxi-

mately equal to the latitude of the location. Hence, for locations on the equator, the optimum angle is horizon-

tal, but we still tilt that panel at an angle to allow the rain to help keep it clean.

The following are illustrations for an area about 30o north or south of the equator.

Figure 7. Different Ways to Orient Solar Panels.

(Solar Energy International - Photovol-

taics Design and Installation Manual)

moresunlight per square

foot falls on a perpendicular

surface (90oangle to the

suns rays is optimal

lesssunlight per square foot

falls on a horizontal surface

lesssunlight per square foot

falls on a vertical surface

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5.0 How Solar Panels Function

A photovoltaic or solar panel converts the energy from the sun into electrical energy by using solar cells.

The Solar panel functions by collecting the energy from the sun, this energy comes in the form of a photon.

The photon is captured by the solar cell and the energy from the photon makes an electron move in the solarcell, which creates a current and electricity.

Figure 8. How a Solar Cell Functions

(www.nrel.gov)

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5.1 IV Curves

Power = Current * Voltage

Figure 9. I-V curve.

(Solar Energy International - Photovoltaics Design and

Installation Manual)

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5.2 Changes in IV Curves





Figure 10. I-V curve affected by temperature.

Figure 11. I-V curve affected by the sun.

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6.0 The Charge ControllerThe charge controller is the brain of the PV system. The wiring from the solar panels, the batteries, and all of

the loads goes through the charge controller. The charge controller manages the ow of electricity from the

panels, into and out of the batteries, and to the loads. It has three main functions:

-Protects the battery from overcharging, by controlling how the PV panel charges the battery

-Protects the battery from discharge, by disconnecting the loads when the battery voltage gets too low

-Gives information on the state of change of the charge controller

Figure 12. Examples of Steca (left) and Morning Star (right) charge controllers.

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7.0 Wiring

The wiring is what carries the electricity from the panels through the charge controller to the batteries

and from the batteries through the charge controller out to the loads.

In a water system, if the pipes are too small, the water will not ow properly through the pipes to where

you need it. This is because of the resistance in the pipe.

Similarly, in an electric system, if the wiring is not sized and installed correctly, the electricity will not

ow properly to the loads. In electrical wiring, the two main considerations are the wire size, and the

terminations.

If the wiring is too small, or if the terminations are not made properly, either of these conditions will

result in too much resistance to the ow of electricity, and the system will not work properly.

7.1 Terminations

To make terminations properly, all wire connections need to be clean and tight. Twisting wires together

and taping them is not good enough. The looseness in these connections adds resistance to the ow of

electricity. The terminations need to be made with the proper connection materials.

7.3 Wire Sizing

When current passes through a wire, voltage is lost as a result of the resistance in the copper wire. This

is an important consideration in all systems, but more so in low voltage (12V e.g.) systems. Losing

2 volts on a 240V system is not too bad since it only represents less than 1% of the voltage lost to

resistance.

But, losing the same 2 volts on a 12V system represents a voltage loss of almost 17% which is quiteexcessive!

The amount of voltage that is lost for a given wire size and current ow is based on how much wire

there is, or the length of the wire.

We never want to lose more than 5% to voltage drop, so on a 12V system, we do not want to lose more

than 0.6V. Table 2, on the following page, is useful to determine the proper wire size.

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Figure 13. Battery wire terminals.

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Table 2. Wire sizing chart.

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As an example:

In Fig. 14, our panel is likely to produce 7 amps of current at 12V during good sun. The wire run from thepanel to the charge controller is 8 meters.

Using the wire sizing chart, if we use 1.5mm2copper wire, the volts lost for 100 meters of wire run and 7 ampsis 15 volts (listed as 15.02 on the chart). But we have 8 meters of wire, so 8/100 of this or 0.08. Therefore,for our example, the voltage lost is 0.08 * 15 = 1.2 V. This is twice as much voltage lost as we want to see,yet, we often see this size wire being used.

From the chart if we use 2.5 mm2wire, the volts lost is .08 * 9.46 or 0.8V. This is very close to what we would

like to see and would be ok, but we would not want to go a longer distance.

If we use 4mm2wire, then our voltage drop is 0.08 * 6 V, or .48V, which is less than the 0.6 volts maximumwe set. So, our best choice here is 4mm2wire.

Figure 14. Example determining wire size.

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In a car when the tank gets low we go to the gas station and ll it up. A solar panel and battery work similarly.

During the day the solar panel lls up the battery with watt hours and at night we take the watt hours out of the

battery to power our lights and radio.

Figure 15. Comparison of a PV cell and Battery V. Gas and a Gas Tank

8.0 Batteries

A PV system is really a battery system with PV panels charging the batteries. Batteries store watt hours just like

a fuel tank stores fuel.

(www.shifting-gears.com/ shift-

ing_gears1.24.99.html)

(www.bpsolar.com)

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8.1 Types of Batteries

There are many types of batteries, the types of batteries that we almost always use are called Lead Acid Batter-

ies. Below is a diagram showing the types of Lead Acid Batteries. Furthermore the types of Lead Acid Battery

we use is a ooded sealed lead acid battery.

Lead Acid Batteries

Flooded

Gel - more expensive

Sealed

Unsealed

(www.absak.com/catalog/

default.php/cPath/1_86_88)

Lead Acid Batteries are made for either car/trucks or solar panels systems. Batteries made for solar panel sys-

tems are called Deep Cycle Batteries.

Designed to release little amounts ofpower over long periods of time

Made to charge at a slow rate also

Solar Batteries - Deep Cycle BatteriesCar/Truck Batteries - Starter Batteries

When possible we want to use thistype

Designed to release a lot of power overa short amount of time

Can be charged at both slow and fast

rates

Figure 16. Types of Lead Acid Batteries.

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8.2 Depth of Discharge

The term depth of discharge just means how far down we drain the battery each night.

The less energy we take out of the battery each night, the longer the battery will last.

A battery that is discharged 50% might last twice as long as a battery that is discharged 80% every night.

So, when we size the battery, we need to keep this in mind. If we determine that we need 100 watt hours of

storage in the battery for each night, then we would want to get a battery that stores twice this amount of watt

hours.

8.3 State of Charge of Batteries

How do we determine how full the battery is or what its state of chargeis? One way is to measure the voltage

using a digital multi meter (DMM). The voltage measurements must be made when

1. Battery is disconnected from the charge controller.

2. Battery has been at rest for 30 minutes.

Figure 17. Battery states of charge.

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8.4 Battery Safety

Batteries can be extremely dangerous. There are three ways in which batteries can hurt someone: chemical, gas

and electrocution.

1.) Chemicals - The acid in the battery is bad for people and for the environment

If the acid from a batterygets on a persons skin it canburn the skin. If the aciddoes touch someones skinquickly apply baking soda tostop the burning

Throwing old batteries intothe woods causes a lot ofproblems to the environment.It can pollute the water killthe plants and animals. Al-ways bring your old batteryback to the place where you

purchase your new battery.

2.) Gas - Batteries vent a gas that be extremely ammable

3.) Electrocution- Batteries have a lot of electricity and can easily electrocute people

Wear goggles and gloves when working with batteriesto protect yourself from the chemicals.

Use wood boxes and shelves to store the batteriesmetal conducts electricity

Always tape the end of your tools and leave only theworking part of the tool exposed.

Never store batteries in an enclosed area allow the gasfrom the batteries to escape never have re or smoke acigarette near a battery.

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9.0 Inverters

(WWF - Energy & Galapagos)

An Inverter is a piece of equipment that converts DC electricity into AC electricity, allowing the PV system to

be used for appliances that require AC current.

There are three types of Inverters: Square wave inverters, modied (quasi) - square wave inverters and sine

wave inverters. Each type of Inverter wave can power different types of electrical equipment.

If you need to power a computer or charge batteries for battery-operated tools, a sine wave inverter is required.

Figure 18. DC vs. AC.

Figure 19. Differenct Types of Inverter Waves

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10.0 Designing a PV System

Fig.14 is a line drawing of a PV System with DC Loads. There are four key parts to the system: Solar

Panel, Battery, Charge Controller, and the Loads.

Figure 20. PV system with DC loads.

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Loads Quantity Watts Hours/Day WattHours/Day

Fluorescent Lamp 2 20 4 160

LED Light 1 1 6 6

DC Outlet (computer or charger) 1 70 1 70

TOTAL 236

10.1 Calculating Total Daily Consumption in Watt-Hours

The rst step in designing a systems is to nd out the total consumption that needs to be powered by

the PV System. Once the total load on the system is known the PV System can be designed. The

rst line has been lled out as an example. Power consumption of common appliances are found in

Sec. 12.0.

Loads Quantity Watts Hours/Day WattHours/Day

TOTAL

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10.2 Efciency of the PV System

Now that we know the loads that we need to provide power for, the next step is in sizing the main components

the solar panels, the battery, the charge controller, and the wiring.

We need to keep in mind, that we need the energy we calculated above available at the loads. But, whenever

energy is produced or moved, there are losses involved, since nothing is perfect. So, we need to size the panels

and the batteries large enough to account for the losses, and still have enough power left over for the loads.

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Figure 21. PV system efciency.



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Air Temperature C + 15 C = Temperature of the Solar Panel

Although Solar Panels need sun to produceenergy, when it is very hot out the solar panelswill not work as well as on sunny days when it iscold. Solar panels function the best at 25oC.Therefore, whenever the solar panel is warmerthan 25oC, it will not produce is rated watt-age.

For every degree that the solar panel temperature is above 25 C the solar panel output 0.5% less. Below is an

example.

If the Air Temperature = 30oC,

30oC + 15oC = 45oC

45oC = Temperature of Solar Panel

Temperature at which the solar panel produces its rated watts = 25oC

45oC-25oC=20oC (this is the amount that the solar panel is above the optimal temperature)

20oC * 0.5% per degree = 10% loss, so the panel output is 90% at 30oC

IN THIS EXAMPLE THE SOLAR PANEL LOSES 10% OF ITS POWER TO TEMPERATURE LOSSES.

PVPanel Output

In a perfect world, a 100 watt solar panel will produce 100 watts of power when the sun is shining on it. But,

this is rarely the case. A solar panel only produces its rated watts under a specic set of conditions:

Perfect sun shining on the panel, perpendicular to the surface

Temperature at 25 degrees Centigrade on the panel surface

Accounting for non-perfect sun:

We take care of the issue with the amount of perfect sun shining on the panel by using the PSH hours for the

hours of sun, instead of counting the hours when the sun is shining. Even though it might look like the sun is

shining brightly for 6 or even 8 hours in a day, we use the PSH value talked about earlier to estimate how many

watthours the panel will produce. For example, one might think that a 100 watt panel would produce 600 or

800 watt-hours in a given day because the sun is shining for 6 or 8 hours. However, if the PSH value for the

area is 3, then we can only count on the panel producing 3hrs * 100 watts, or 300 watthoursin a given day.

Accounting for non-standard Temperature:

As stated above, the panel produces its rated watts when the temperature of the panel surface is 25 degrees C.

So, we have to adjust for the times when the panel surface is NOTat 25 degrees C.



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To summarize, if we install a 100 watt solar panel in an area with a PSH of 3.0 and where the average air

temperature is 30 degrees C, we can expect to produce from this panel:

But, this output is still at the panel, and not at the load. We still have to get the energy through the wiring and

through the battery. We will lose some energy at each place.

Battery EfciencyMost batteries have an efciency rating of about 85%. This means when energy passes through the battery,

about 15% of the energy is lost.

Wiring Efciency

Earlier, we talked about the need to use larger wire so we dont have a large voltage drop. We wanted to keep

the voltage drop to 5% or less.

When we lose volts because of wire that is too small, this also means we lose energy because volts multipliedby amps = watts.

So, we need to include a loss factor for what we lose in the wire. If we size the wire correctly, this loss factor

could be as little as 3%. If we use too small, or too long a wire then this factor could be over 10% which is way

too large.

30

Battery Efciency is 85% or 0.85

Properly designed wiring may have a combined efciency of 97% or 0.97

100W Panel x 90% (because of loss due to temperature) x 3 PSH per day

= 270 watt-hrs per day of energy output.

Figure 22. PV panel output.



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10.3 Sizing the Panel

In taking all loses into account, the PV array size can be found by dividing the total number of watt hours re-

quired in a day by the multiplication of the PV panel output, battery efciency and wiring efciency. If we have

a condition where the air temperature is 30oC on average, we have a battery, and the wiring is sized correctly,

then the power delivered to the load from a 100 watt panel would be:

100W x 90% for temp. loss x 85% for battery losses x 97% for wiring losses = 74W

Next, multiplying 74W by the Peak Sun Hours (PSH), in one day in an area with a PSH of 3.0, the energy, inwatt-hours, available at the loads from a 100 watt panel would be:

74 watts * 3 hours of perfect sun = 223 watt-hrs

This is quite different than if we had assumed no losses and hoped to get 100 watts of power for 3 hours or

300 watt-hours. It is even more different than if we had hoped to get the 100 watts of power for all 6 hours

when the sun appears to be shining, or 600 watthours. So, it is very important to take all of these factors into

consideration when sizing the panel, or we will end up with a panel that will not properly charge the battery, and

our system will fail.

To size the panel, knowing the loads helps to combine these factors into a Panel Factor. For example, in thiscase, our panel factor would be 74% or 0.74 since we can expect to get 74% of the 100watt rated power of the

panel, or 74 watts. We often use a factor of 75% as a round number.

So, if for example, we had calculated the required loads to be 230 watt-hours per day, similar to the previous

example, then we would have to divide the 230 watthours by the panel factor to see how many watt-hours we

need to produce to overcome the losses.

230 watt-hrs / 0.75 = 307 watt-hrs

In an area with a Perfect Sun Hour (PSH) rating of 3.0, we would have three equivalent hours of sun to produce

these watthours, so we need a panel to be:

307 watt-hrs / 3 hours = 102 watts

We would purchase a solar panel rated at least 100 Watts. But for battery charging considerations, a larger panel

would be better to be able to ll up the battery more quickly following time with low sun.

This example was for a DC system, with no inverter. A charge controller is quite efcient in passing through

electricity, but the inverter does incur losses. If an inverter is in the system, we will have to add another loss

factor. Inverters are typically 85% to 90% efcient. So, with an inverter in the system, the panel and the battery

would need to be even larger.

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Figure 23. Sizing a PV system.



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10.4 Battery Sizing

The next step in the design process is to size the battery. We said before that the battery stores energy in wat-

thours, like a fuel tank stores fuel. And, we said that the battery has an efciency of 85%, meaning we lose 15%

of the energy in moving it through the battery. If we use our example of a load of 230 watthours, then we would

need a battery sized at:

230 watt-hrs / .85 for efciency = 271 watt-hrs

But, if we sized the battery at 271 watthours, this would mean that:

We would not have any energy left in the battery on days when the sun does not shine to charge the

battery back up.

We would also be completely discharging the battery every day, which we said earlier is very bad for the

battery.

So, we have to size the battery with these two considerations in mind:

Days with No Sunshine

We have to make some kind of guess as to how many days we want to keep the system working with no sun.

One day is obviously not enough. But, if we try to make it too long, the battery gets too big and expensive.

Often, we use three days as a good design range for providing for power with no sun.

So, to provide for three days of no sun, we would need the battery to store:

271 watt-hrs needed per day x 3 days with no sun = 813 watt-hrs

Prevent the Battery from Discharging More than 50%

The above sized battery would still have us completely discharging the battery during those times when there is

no sun for three days. We said earlier that we did not want to discharge the battery any further than half. So, we

would need to have a battery that would hold twice as many watthours as we need.

813 watt-hrs x 2 for depth of discharge = 1626 watt-hrs

So, we actually took our daily watt-hour requirement and multiplied it by 6. This was three times larger for the

days with no sun, and two times larger for the depth of discharge reasons.

271 Watt hours

271 Watt hours

271 Watt hours

271 Watt hours

271 Watt hours

271 Watt hours Keeping maximumdischarge at 50%.

For 3 days withoutsunshine.

33


{Total =1626 watt-hrs


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Batteries however are not sold in Watt Hours, but are rather sold in Amp Hours therefore we have to do more

math to gure out how many Amp hours we need. Usually batteries are 12 Volts using the below formula we

can nd out amphours.

Using the equation for our example we get:

Changing the days without sun, and the allowable depth of discharge can make a big difference in the size of thebattery.

For example, if we said we only needed to provide for two days with no sun, and we could discharge the battery

to 55%, then the battery size would be:

230 watthours / 0.85 for battery loss = 271 watt-hrs

271 watthours x 2 days with no sun = 542 watt-hrs

542 watthours / .55 for depth of discharge = 985 watt-hrs985 watthours / 12V = 82 Amphours

So, we need to understand what we are providing for when we size, and purchase a battery. It might be

necessary for cost or portability, in this case to purchase the smaller battery. But, we need to know that we are

giving up the one day of energy without sun when we make that decision.

Watthours

= Amp Hours

Volts

1626 Watt Hours =136 Amp hours 12 Volts



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11.0 System Installation

The best designed solar power system will not perform well if it is not properly installed. Care must be given to

the proper installation of all of the items included in the system.

11.1 Connecting Solar Panels in Parallel and SeriesThere are two ways to connect Solar Panels and batteries: series and parallel. When connecting in series the

voltage is added and the amperage stays the same. When connecting in parallel the voltage stays the same and

the amperage is added. The below examples are for solar panels, however batteries can be connected in the

same way.

24 Voltsat 3.5 Amps

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12 Voltsat 7 Amps

Figure 24. Series connection.

Figure 25. Parallel connection.

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24 Voltsat 7 Amps

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Remember you cannot connect different types of panelsor batteries together in one series run or parallel run!

Figure 26. Series and parallel connection.



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11.2 Installation of the Solar Panel

Aiming or Orientation

The earlier sections on design showed that to get the maximum output from the panel, it needs to be oriented to

the sun properly.

The panel should mounted on an angle approximately equal to the latitude of the area, and pointing to the

equator.

(If you are in the southern hemisphere, aim the panel to the north, and if you are in the northern hemisphere,

aim the panel to the south.)

So, for example, Mae Sot is at about 17degrees north of the equator, so the proper orientation for the panel

would be to tilt the panel at 15 to 20 degrees, aimed south, toward the equator.

If you are very close to the equator, then the latitude is close to 0 degrees. In these areas, the optimum angle for

maximum power might be at, but it is still good to tilt the panel 5 or 10 degrees to let the rain help to keep the

panel free of dust and dirt.

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Shading

If any portion of the panel is shaded at any time during the day, its power output will be signicantly reduced.

Quite often, panels are installed where there is no shading, but since trees and bushes grow quickly in some

areas, they become shaded, so this is a continuing maintenance item.

Sturdy

The panel must be installed on sturdy mountings so its orientation will stay as originally designed, and so it will

not be subject to being knocked.

Often times, it works to mount the panel on the roof. This should only be done if the roof is sturdy and is

aiming in the right direction. If this is not the case, it would be better to mount the panel on its own supports.

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Cabling from the Panel to the Controller

The cabling from the Panel to the Controller should be sized large enough, and kept as short as possible, and

located where it will not be a hazard or be pulled down.

At the panel location and at the building location, secure the cable tightly so that

-There is no tension being placed on the junction box of the panel

-There are no sharp edges where the cable enters the building.

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11.3 Controller Installation

The controller needs to be mounted in a location where there is not a lot of activity, to avoid the possibility of

being knocked into by carried items. It needs to be mounted securely to the wall, in a place where the cables

coming into it and going out of it can be secured independently to the building.


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11.4 Installation of the Battery

The battery needs to be close to the controller to limit the length of the wire, and reduce the losses in this cable.

It should be in a non-metallic battery box (wood or plastic) vented to the air, and covered so nothing metal can

be placed on top of the battery.

11.5 Wiring Installation

Wiring should be neat, and fastened securely in all locations. This makes checking for trouble much easier, andavoids problems of things being hung on the wiring or cutting into the wiring.

The wiring needs to be large enough to avoid voltage drops.

Strain relief should be provided at all points where the wiring is terminated to avoid tension on the connection.

All terminations should be made with proper connection equipment (wire nuts or terminal strips). Try to avoid

just stripping, twisting, and taping for connections, as this leads to early failures.


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11.6 Light Switch Installation

Give some thought to the location of the light switches.

First of all, try to install a separate light switch for every light. This way if only one light is needed, the others

can remain off.

It is good to install all of the light switches at the controller location, because this reduces the number of eld

terminations and connections, and points of potential failure. Then, all of the cables are direct runs from the

controller to the lights. If it is important to install a switch away from the controller and closer to the light, it is

best to make all of the terminations at the light or in the switch, and not just breaking into the wire run to cut in

a switch.

11.7 Load Connections

All wiring to loads must be connected through the charge controller. No wires should be terminated on thebattery except for the wires going to the charge controller. If loads are connected directly to the battery, then

these loads are not disconnected when the charge controller decides to turn the loads off to protect the battery,

and the battery will fail prematurely.

Switches

42

No!



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ITEM LOAD (Watts)Air Conditioner 1500

Blow Dryer 1000

Ceiling Fan 10 - 50Clock Radio 5

Clothes Washer 1450

Electric Clock 4

Iron 1500

Sewing Machine 100

Table Fan 10-25

Refrigerator/Freezer (19 Cu Ft.) 1000 Wh / day



Refrigerator/Freezer (10 Cu Ft.) 280 Wh / dayRefrigerator/Freezer (4 Cu Ft.) 210 Wh / day

Blender 350

Coffee Pot 1200

Microwavyy (.5 Cu. Ft.) 750

Electric Range 2100

Incandescent (100 W) 100


Compact Fluorescent (60W equaivalent) 16


Compact Fluorescent (40W equaivalent) 11

CB radio 10

CD player 35

Celular Telephone 24

Computer Printer 100

Computer (desktop) 80-150

Computer (laptop) 20-50

Stereo (average volume) 15

Stereo (Large full volume) 150

TV (12 inch black & white) 15TV (19-inch color) 60

VCR 40

Band Saw (14) 1100

Circular Saw (7.25) 900

Disc Sander 9 1200

Drill (1/4) 250

Drill (1/2) 750

Drill (1) 1000

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Table 3. Common Loads.

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To have good load management you need to:

1.) Pay extreme attention to using only what youdesign for.

2.) If you have even 1 day with no sun - cut

back your use of the system that day.

3.) If possible - design the system to produce20% to 50% more than your design require-ment.

WHEN YOUR CHARGE CONTROLLER DISCONNECTS THE LOAD - THIS MEANS

THE BATTERY BANK HAS BEEN USED ALL THE WAY DOWN THROUGH ITS

THIRD DAY OF RESERVE AND WILL TAKE 3 DAYS OF GOOD SUN WITH NO LOADTO CHARGE BACK UP.

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13.1 Wire Connections

Go around to all of the wire connections and check for tightness and that they are free of corrosion and dirt.

Often you will nd a loose wire connection and that will be the end of it.

If the wire terminations at the battery are becoming corroded and if the battery is dirty, take the connections

apart, clean the terminals and re-tighten them.

13.2 Battery

You will need to check the state of charge of the battery. This is done by disconnecting the battery from the

system and letting it sit for about a half hour and using a multi-meter to check the voltage.

Earlier in Sec. 8.3, we showed how the voltage reading relates to the state of charge of the battery:

If the battery is low, and you think there is no reason for it to be low such as there has been good sun for

several days, then the problem could be:

The battery is not getting properly charged. (which could be caused by a faulty solar panel or a faulty

charge controller)

The battery was discharged so deeply that its voltage is so low it cant be recharged by the solar system.This could have happened by by-passing the charge controller and connecting loads directly to the

battery.

To determine if the charge controller is charging the battery, in good sun:

With the battery still disconnected, measure the voltage where the wires from the solar panel come into the

charge controller. It should be an open circuit voltage between 17 and 20 volts.

Then connect the battery to the charge controller and see if a charging voltage is being sent to the battery. This

voltage might be around 14 volts.

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13.3 Solar Panel

If it does not appear that the solar panel is providing the output required to charge the battery, we can check its

open circuit voltage and short circuit current.

This should be done with the wiring from the solar panel completely disconnected from the charge controller.

Before checking the voltage and current, it is good to check inside the junction box (if it is accessible) to be surethat the diode has not been burned up. This can sometimes happen if a battery is connected in reverse polarity

and this reverse current passes through the charge controller and out to the panel. If the diode is burned up,

remove it. For a single panel installation, the diode is not necessary.

13.4 Check Load Terminals

If the voltage at the panel connection to the charge controller is correct, and if no voltage is being sent to the

battery, or to the loads then the controller might be bad.

However, some controllers have a minimum voltage level they need from the battery in order to even turn on. If

the voltage of the battery is so low that it is below this minimum voltage level, than the charge controller might

be ne, even though it will not turn on. In this case, you will need to change the battery out for a good one to

test the system.

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14.0 About Us

Green Empowerment

Green Empowerment is a public non-prot international development organization based in Portland, Oregon

that is supported by individual donors, foundations, businesses, and international and governmental aid orga-

nizations. Our mission is to promote community-based renewable energy projects internationally to generate

social and environmental progress. Since our inception in 1997, we have developed a strong administrative

structure. We have a diverse funding base, important national & international partnerships, and a solid track

record.

Our Projects are usually associated with:

-Residential lighting and electricity

-Power for schools and clinics

-Energy for economic development and micro-enterprise

-Comprehensive community environmental plans and watershed protection

-The protection, development and accessibility of potable water sources

-Potable water pumping

We utilize small hydropower, biomass, wind and solar power projects to energize communities and stimulate

positive social and economic advances in an environmentally safe manner. All projects have a strong environ-

mental protection component that includes watershed mapping, resource conservation, and restoration activities.

We emphasize local leadership, community participation and long-term economic and environmental sustain-

ability. We partner with NGOs (non-governmental organizations) engaged in renewable energy projects. We

assist with feasibility studies, project planning, technical training and project fund raising, looking to the local

NGOs and communities to determine project priorities and goals.

Green Empowerment is committed to promoting renewable energy and sustainable development around the

world. We believe that access to electricity is fundamental to improving the quality of life and raising the stan-

dard of living for people everywhere. Our goal is to support community-based, renewable energy projects that

are economically and environmentally viable and that foster self-sufciency and true independence.

Contact Information:

Green Empowerment

140 SW Yamhill St. Portland, OR 97204, USA

(tel) 503-284-5774 (fax) 503-460-0450

[email protected]

www.greenempowerment.org

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Palang Thai

Palang Thai is a Thailand-based non-prot organization dedicated to empowering grassroots communities and

small entrepreneurs to use renewable energy in ways that support sustainable development and participatory

democracy. Palang Thai has helped conduct hands-on trainings on renewable energy in Mykyina, Shan state in

Burma, and has helped TOPS and villagers to build two micro-hydro systems in Tak province, Thailand.


Palang Thai

315/247 Sathupradit Soi 19, Bangkok, Thailand 10120

(tel) 662-674-2533 (fax) 662-6740-2533

[email protected]

www.palangthai.org

International Institute for Energy Conservation

IIEC is a non-governmental (NGO), not-for-prot organization with ofces in Africa, Asia, Latin America,

and North America. It was established in 1984, to foster the implementation of energy efciency in developing

countries and countries in transition. IIEC has full time local staff in each of its ofces that are well placed

to contribute to programs due to their extensive exposure to energy, transport and environment activities

in the region and their understanding of cultural issues relevant to the countries. As an organization with

proven technical capabilities, IIEC designs policies, implements programs, and supports institutions that

mainstream energy efciency in the entire value chain of energy systems and use. IIECs approach focuses on

implementation, resulting in policies developed in partnership with key policy makers and industry in our target

countries as well as the bilateral and multilateral institutions that help to shape energy policy and investmentpriorities globally.


IIEC-Asia (Regional Ofce), Thailand

12th Floor, United Business Center II Bldg.,

Suite 1208, 591 Sukhumvit Rd. (Soi 33)

Wattana, Bangkok 10110 -- THAILAND

Tel: +66.2.662.3460-5

Fax: +66.2.261.8615

Email: [email protected]

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Other Coordinators

Karen Health and Welfare Department

The Karen Health and Welfare Department (KHWD) (not part of the government) has, over the years, built upa network of medics and clinics operating inside Burma. They support over 36 clinics with a roster of approxi-mately 75 surgeons, medics, and nurses. The medics treat land mine victims and other casualties of the conict

and grinding oppression. More information: http://www.greenempowerment.org/burma.htm

Taipei Oversees Peace Service (TOPS), Thailand

TOPS in Thailand provides various humanitarian assistance, mainly educational programs, for refugees andlocal people affected by the inux of refugee populations and migrant workers who have ed from ghting orvarious type of persecution, mainly from Burma . TOPS recognizes that through full participation in decision-making, the participants in programs will become more condent in themselves, be able and willing to sharemore responsibilities of the programs and thereby become more self-reliant in dealing with the challenges inany aspects of their life. More information: http://thailand.tops.org.tw/ENG.HTM,Contact info: [email protected]

Zoa Refugee Care

ZOA REFUGEE CARE (ZOA) is an international NGO, operating in more than 10 countries worldwide.ZOA supports (former) refugees, internally displaced persons (IDPs), returnees and others who are affected byconict or natural disasters. More information: htpp://www.zoaweb.or, Contact info: [email protected]

Instructors

Walt Ratterman, Green Empowerments Field Director of Programs, has over 30 years of experience in

electrical construction. He is a NABCEP-certied solar system installer. He completed the Masters of Science

Program in Renewable Energy at Murdoch University in Australia (via the internet) in 2002, specialized

in renewable energy for the developing world. Walt currently serves as vice president of Knightsbridge

International- a non-prot, volunteer based, humanitarian aid organization. With Knightsbridge, Walt hasworked on projects in Thailand, Cambodia, Burma, Mongolia, Nicaragua, Philippines, Afghanistan, Ecuador,

and Nicaragua. Contact info: [email protected]

Chris Gracean has worked on technology and policy aspects of renewable energy in a variety of challenging

social and cultural contexts including Native American reservations, North Korea, Burma, and the post-restruc-

tured California energy industry. His Ph.D. research at the Energy and Resources Group (ERG, UC Berkeley)

focused on community-managed micro-hydroelectricity in Thailand, where he has lived since 2000. Besides an

MS and Ph.D. from ERG at U.C. Berkeley, he has a BA in Physics from Reed College. He has published over

40 articles on renewable electricity and energy policy. Contact info: [email protected]

Workbook Authors

Walt Ratterman

Seth Kassels

Dipti Vaghela

Sirikul Prasitpianchai (Thai translation)

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Green Empowerment and Palang Thai Photovoltaic System, Training Manual - Additional Notes

Notes:


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